The invention relates to an arrangement for the remote-controlled release of active ingredients according to the species of the patent claims.
In different areas of technology and biomedicine, of medical engineering in particular, there has been a continuing need for a remote-controlled release of substances out of a storage system, such as a capsule, at locations that cannot be accessed directly (e.g. within the human alimentary tract) at a desired time and without connecting this storage system via hoses, electrical lines or the like.
According to the state of the art, various means and methods are particularly known for the remote-controlled release of active ingredients within the digestive system which use capsules with a relatively complex structure. Typical examples are the so-called RF capsules [S. P. Eriksen et al., J. Pharmaceutical Sciences 50 (1961) p. 151], a small intestine capsule [A. Hemmati, Dtsch. Med. Wschr. 93 (1968) S. 1468], an HF capsule [B. Hugemann and O. Schuster, German Patent Document DE 29 28 477 (1979)], an InteliSite® capsule [A. F. Parr et al., Pharmaceutical Research 16 (1999) p. 266] and a marker for intestine diagnostic and therapeutic measures [W. Andrä und M. Wendt, DE 197 45 890 (1999)]. Other capsules are described in the U.S. Pat. Nos. 4,239,040 and 5,279,607.
All designs of the capsules known have at least one of the following disadvantages:                1. Some capsules consist of bio-incompatible components. Some include batteries, other capsules contain different metals in the form of spring bodies, heating wires or electrical conductors. Therefore, these capsules must be protected by a hermetic bio-compatible enclosure. The unintentional damage to this enclosure involves the risk that the toxically acting content comes into contact with the body tissue.        2. Other capsules have a rigid form and cannot be dissolved within the digestive system. Thus, before the capsule is swallowed, it must be ensured that the digestive system is free of stenoses on which these rigid capsules could be caught, because in such a case an operation would be necessary to remove them.        3. The principle on which the effect of some capsules is based is that in an electrically conductive part a alternating magnetic field induces eddy currents or magnetic losses that cause a temperature rise and, if a threshold temperature is reached, the opening of a seal. However, the alternating magnetic field generated outside the human body does not only have an effect in the specific partial volume of the capsule that is provided for the temperature rise but also in the electrically conductive body tissue. To avoid an excessive temperature rise by eddy currents at these locations, the product of the amplitude H and the frequency f of the magnetic field must remain under a maximum value (in the following referred to as “Brezovich Limits”), which has for example been indicated for the whole-body exposition as 4.85×108 A/(s×m) [I. A. Brezovich, Medical Physics Monograph 16 (1988), p. 82]. Thus, the alternating field output that can be converted into heat is limited and the reliable release function is restricted.        